The Lincolnshire Bird Club

By chance I recently came across a report from 1980 prompting discussion around the implications being considered for reclamation of the coastal saltmarshes for agriculture, but also taking into account the requirements of conservation and other interests on the coast.

Although this considered the whole of the Lincolnshire coast, a more detailed section on ornithology largely dealt with the bird populations on the Wash. It provides an interesting (and somewhat depressing) account of some key species and the subsequent effects of reclamation and enclosure in the 1970s.

I have summarised some of the key species information relating to the Lincolnshire Wash below. Remember this information was written 35 years ago. The changes for some species are stark.

Saltmarsh habitat

In 1973 there were approximately 4,457ha of saltmarsh on the Wash and about 2,600ha (58%) sufficiently free of flooding in summer to be used by nesting birds. Between 1974 and 1978 about 698ha of this area which comprises the mid and upper levels of marsh were enclosed. The greatest variety and highest densities of breeding birds occurred on the largest areas of saltmarsh where the upper levels of marsh are allowed to develop. Frampton and Kirton Marshes exhibit a greater diversity in vegetation structure than most of the other marshes around the Wash and support a wider variety of breeding birds (12 species).

Some key species accounts

Twite – The importance of the Wash for this species is acknowledged with estimates that 40,000 out of a national total of 65,000 (67%) of wintering Twite feeding on the saltmarshes of the Wash. It was estimated that the section of Wash coastline in the Gedney-Holbeach area supported between 5,000 and 6,000 Twite, which is approximately 10% of the British total.

Shelduck – It was noted that in 1978 there were 91 pairs on Frampton and Kirton Marshes and 18 pairs on those of Holbeach and Dawsmere.

Black-headed Gull – The main colony of Black-headed Gulls within the wash is situated on the Frampton and Kirton marshes. In recent years it has contained at least 8,000 pairs and in 1974 there may have been as many as 22,000 pairs. This colony is one of the ten largest in Britain and Ireland. It also noted that until enclosure displaced them there was a sizeable colony at Bennington until 1972. The Wash breeding population of Black-headed Gulls represents at least 8% of those breeding in England and Wales, estimated to be between 100,000 and 111,000 pairs in 1973.

Common Tern – In recent years the main colonies have been on Frampton and Kirton marshes (since 1966) up to 120 pairs

Birds of prey – Written in the context of the whole Wash, so not specifically Lincolnshire the report noted that in most years, several pairs of Short-eared owls have attempted to nest amongst the sea couch grass on the sea walls and highest saltmarshes of the Wash whilst a pair of Montagu's Harriers, now a very scarce breeding species in Britain, bred successfully in three years, 1970-72, close to the Wash

Passerines – Skylark densities ranging between 79 and 140 pairs/km2 were recorded on the Gibraltar Point, Terrington and Dawsmere saltings. This was noted as being high compared with other areas and habitats as densities are usually below 30 pairs/km2 on most farms. The densities of Meadow Pipits on the upper saltmarsh at Dawsmere and Gibraltar Point are also high for lowland Britain, whilst densities of Reed Buntings on the four relatively high, ungrazed saltmarsh plots, including Gibraltar Point, were considerably higher (50-80pairs/km2) than those on the two lower areas that were grazed (8 and 17 pairs/km2)

The effects of saltmarsh enclosures on breeding birds.

The report noted that the construction of a seawall around an area of marsh prevents tidal incursions but whilst the saltmarsh vegetation remains intact, the breeding populations of Redshank remained little affected.

There is a drastic change once the creeks are infilled, the saltmarsh is ploughed up and the land is converted to arable. Skylarks continued to breed at a reduced density (probably less than 30 pairs/km2 compared with 80 or more on the unenclosed upper saltmarsh). Lapwings, Oystercatchers and Ringed Plovers used the cultivated fields adjacent to the seawall for nesting.

The more recent enclosures on The Wash have resulted in the loss of a substantial proportion of the upper levels of salting where the majority of birds nest. In May and June, spring tides which exceed the height of 3.0m O.D. can destroy many nests on all but the highest levels of marsh. The marsh which remains outside the seawall is particularly vulnerable to tidal inundations during the breeding season for many years until its level has been built up by accretion. It is clear from the salting vegetation that there are only limited areas on the Wash where the more mature marsh has been allowed to develop.

The following examples indicate the effects of enclosures and subsequent developments on saltmarsh breeding birds.

The 1972 enclosure of 288ha of Bennington Marsh destroyed the nesting habitat for about 450 pairs of Black-headed Gulls, 35 pairs of Common Terns and 100 pairs of redshank.

The destruction of 303ha of saltmarsh following the enclosure of Wainfleet marsh between 1976 and 1978 has resulted in the loss of nesting habitat of another 100 pairs of redshank. The majority of the Redshank have probably not been accommodated elsewhere in the Wash.

It would appear Redshank is the species hardest hit by enclosures

The report notes that densities of Redshank on the mid and upper levels of the wash saltings are amongst the highest recorded in Britain. And yet….

The enclosure of 144ha of the Lincolnshire portion of Terrington Marsh in 1974 included the 50ha plot which held a minimum of 26 pairs in 1973. The conversion of saltmarsh to arable within the enclosure is estimated to have destroyed the nesting habitat of the majority of the 75 pairs of Redshank.

A summary table detailing the effects on the Redshank population as a result of enclosures details the following;

Bennington marsh – 288ha enclosed in 1972 – estimated 109 pairs of Redshank lost
Terrington (Lincs) – 144ha enclosed in 1974 – estimated 75 pairs lost
Wainfleet – 71ha enclosed in 1976 – estimated 27 pairs lost
Wainfleet – 232ha enclosed in 1978 – estimated 88 pairs lost
Freiston – 35ha enclosed in 1978 – estimated 13 pairs lost
Gedney Drove End – c12ha enclosed in 1978 – estimated 6 pairs lost
Gedney Drove End – proposed 82ha to be enclosed – possible loss of 41 pairs

About 350 pairs of Redshank (a quarter of the 1973 breeding population) lost their nesting habitat on the Lincolnshire Wash following the conversion of 881ha of saltmarsh to arable between 1972 and 1978.

Although conservation efforts in recent time around the Wash may have gone a small way to redressing the balance for some species, I fear we will never see anything like the numbers quoted for some of the above ever again. Although I acknowledge this is not a sole result of reclamation, I have no doubt it has been a significant contributory factor.